title: Labeling of cancer cells with magnetic nanoparticles for magnetic resonance imaging.
abstract: OBJECTIVE
  The process of invasion and metastasis formation of tumor cells can be studied by following the migration of labeled cells over prolonged time periods. This report investigates the applicability of iron oxide nanoparticles as a magnetic resonance imaging (MRI) contrast agent for cell labeling.
  
  
  METHODS
  γFe2 O3 nanoparticles prepared with direct flame spray pyrolysis are biofunctionalized with poly-l-lysine (PLL). The nanoparticles within the cells were observed with transmission electron microscopy, bright-field microscopy, and magnetorelaxometry. MRI of labeled cells suspended in agarose was used to estimate the detection limit.
  
  
  RESULTS
  PLL-coated particles are readily taken up, stored in intracellular clusters, and gradually degraded by the cells. During cell division, the nanoparticle clusters are divided and split between daughter cells. The MRI detection limit was found to be 25 cells/mm(3) for R2*, and 70 cells/mm(3) for R2. The iron specificity, however, was higher for R2 images. Due to the degradation of intracellular γFe2 O3 to paramagnetic iron ions within 13 days, the R1, R2, and R2* contrast gradually decreased over this time period to approximately 50% of its initial value.
  
  
  CONCLUSIONS
  These results suggest that PLL-coated γFe2 O3 nanoparticles can be used as an MRI contrast agent for long-term studies of cell migration. Magn Reson Med 71:1896-1905, 2014. © 2013 Wiley Periodicals, Inc.
authors.affiliation: Department of Physics, University of Erlangen-Nuremberg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Weis
authors.forename: Fabian
authors.initials: F
authors.lastname: Blank
authors.forename: Adrian
authors.initials: A
authors.lastname: West
authors.forename: Gregory
authors.initials: G
authors.lastname: Black
authors.forename: Robert C
authors.initials: RC
authors.lastname: Woodward
authors.forename: Matthew R J
authors.initials: MR
authors.lastname: Carroll
authors.forename: Astrid
authors.initials: A
authors.lastname: Mainka
authors.forename: René
authors.initials: R
authors.lastname: Kartmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Brandl
authors.forename: Heiko
authors.initials: H
authors.lastname: Bruns
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hallam
authors.forename: Jeremy
authors.initials: J
authors.lastname: Shaw
authors.forename: John
authors.initials: J
authors.lastname: Murphy
authors.forename: Wey Yang
authors.initials: WY
authors.lastname: Teoh
authors.forename: Katerina E
authors.initials: KE
authors.lastname: Aifantis
authors.forename: Rose
authors.initials: R
authors.lastname: Amal
authors.forename: Mike
authors.initials: M
authors.lastname: House
authors.forename: Tim St
authors.initials: TS
authors.lastname: Pierre
authors.forename: Ben
authors.initials: B
authors.lastname: Fabry
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D058948:Cell Tracking / Q000379:methods*; D003287:Contrast Media / Q000737:chemistry; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009361:Neoplasm Invasiveness; D009374:Neoplasms, Experimental / Q000473:pathology*; D010316:Particle Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods; D013552:Swine
chemical_list: D003287:Contrast Media; D058185:Magnetite Nanoparticles
keywords: cancer metastasis; iron oxide; magnetic resonance imaging; molecular imaging; nanoparticles; relaxometry